Final answer:
The correct answer to the student's question is B. ecosystem, which is the functional unit studied by ecologists exploring the interactions between living and nonliving elements within a specific region.
Step-by-step explanation:
Understanding the Functional Unit of Ecology
Ecologists study the interactions between the biotic factors (living things) and abiotic factors (non-living things) within a given area. This unit of study is known as an ecosystem. An ecosystem includes all the interdependent elements: plants, animals, microorganisms, water, soil, and climate, to name a few. It may be as large as a forest or as small as a fallen log. Ecologists research various ecosystems to understand the dynamic balance among organisms and how they manage resources such as nutrients and energy.
In answering the student question, the functional unit or region that ecologists study, which consists of the physical conditions and the interactions between the plants and animals inhabiting the area, is best described as option B. ecosystem. The other options do contribute to ecological studies but represent different levels of biological organization: A. biome refers to a large area with similar climate and life forms; C. biosphere encompasses all ecosystems on Earth; D. habitat describes the specific area where an organism lives.